This invention relates to a golf ball comprising a core and an enclosure of one or more layers enclosing the core, and more particularly, to a golf ball of such structure which has a great resilience, a good feel when hit, ease of control upon iron shots, and minimized flaw on the cover surface.
Traditional cover stocks used in prior art golf balls include ionomer resins and trans-polyisoprene rubber which is also known as balata rubber. In particular, the golf balls using balata rubber win the favor of those golfers who take more account of control and feel.
The balata covers, however, are inferior to the ionomer covers with respect to resilience, distance, and scuff resistance upon iron shots. They need further improvements. There is a desire to have a golf ball which not only has a great resilience and distance, but is also improved in scuff resistance, controllability and feel.
An object of the invention is to provide a novel and improved golf ball comprising a core and an enclosure of one or more layers enclosing the core wherein the enclosure is improved so as to acquire a great resilience, extended distance and pleasant feel and enhance scuff resistance and controllability.
Regarding a golf ball comprising a core and an enclosure of one or more layers enclosing the core, the inventor has found that when at least one enclosure layer is formed of a rubber composition comprising a base rubber based on polybutadiene having a cis-1,4-structure, an xcex1,xcex2-unsaturated carboxylic acid, a metal oxide, and a polymerization initiator in a specific proportion, quite unexpectedly the resulting golf ball is endowed with good controllability and pleasant feel similar to balata rubber and satisfies all the requirements of resilience (or rebound), flight distance and scuff resistance.
Accordingly, the invention provides a golf ball comprising a core and an enclosure of one or more layers enclosing the core. At least one layer of the enclosure is formed from a rubber composition comprising 100 parts by weight of a base rubber based on a polybutadiene having at least 40% of cis-1,4-structure, 5 to 40 parts by weight of an xcex1,xcex2-unsaturated carboxylic acid, 5 to 40 parts by weight of a metal oxide, and 0.1 to 5 parts by weight of a polymerization initiator, by subjecting the rubber composition to crosslinking reaction.